The present invention relates to a structure and method for linking a propeller shaft and an axle device in a power transmission device comprising a propeller shaft that transmits drive force from an engine and an axle device that transmits the rotational drive force of the propeller shaft to the left and right wheels in an automobile or the like.
Power transmission devices that transmit engine drive force to the wheels of a front-wheel-drive or four-wheel-drive automobile, for example, are frequently configured such that rotational drive force is transmitted from a transmission to an axle device via a propeller shaft. For instance, in one configuration the engine is installed at the front of the vehicle, and the output rotation from the transmission coupled to the engine is transmitted through a propeller shaft to the rear axle device. A variety of such power transmission devices have been known in the past, and are disclosed in Japanese Laid-Open Patent Applications H10-194004 and H7-8632 and elsewhere.
A problem that is encountered, however, is that if there is any imbalance in the rotating members in the power transmission device, this imbalance tends to cause vibration during rotation transmission. Rotational imbalance is particularly apt to occur when the propeller shaft is a long, cylindrical member extending longitudinally along the chassis. Also, the coupling devices that couple the propeller shaft to the axle device or the like are prone to rotational imbalance because the yoke flanges, companion flanges, and other constituent parts thereof are forged parts, and therefore do not have perfect rotational shapes (annular or cylindrical shapes).
Because of this, propeller shafts are measured by themselves for imbalance, and are balanced by attaching adjustment weights that cancel out the imbalance. With axles, the runout during rotation is measured with the axle in an assembled state, at the end face and outer peripheral surface of the companion flange attached to the input member end of the axle, and [the components are] put together such that the imbalance caused by this runout cancels out the imbalance of the propeller shaft coupled to the companion flange.
With this balancing method, the rotary system of the axle must be rotationally driven and the runout of the companion flange measured with the axle in an assembled state, and furthermore measurement is required for each and every axle, so a tremendous amount of labor and cost are entailed by this measurement.
It is an object of the present invention to provide a structure and method for linking a propeller shaft and an axle input member so that the occurrence of rotational imbalance can be effectively suppressed.
It is a further object of the present invention to provide a linking structure and method with which the measurement of rotational imbalance, and the adjustment thereof, can be carried out more simply.
The linking structure pertaining to the present invention links the propeller shaft and the rotation transmission device in a power transmission device (such as the transfer mechanism TF or the rear axle device AR in the examples) comprising a propeller shaft that transmits rotational drive force and a rotation transmission device that is linked to the propeller shaft and transmits rotational drive force. In this linking structure, a first mark indicating the rotational imbalance direction in the propeller shaft is provided to the propeller shaft, a second mark indicating the rotational imbalance direction in a companion flange that is linked to the propeller shaft in the rotation transmission device is provided to this companion flange, and the propeller shaft and the companion flange are linked on the basis of the first and second marks.
In this linking structure, it is preferable if the first mark is provided in the direction in which the unbalanced rotational mass of the propeller shaft becomes lighter, the second mark is provided in the direction in which the unbalanced rotational mass of the companion flange becomes heavier, and the propeller shaft and the companion flange are linked such that the first and second marks are as close together as possible. The structure may also be the opposite of this, in which the first mark is provided in the direction in which the unbalanced rotational mass of the propeller shaft becomes heavier, the second mark is provided in the direction in which the unbalanced rotational mass of the companion flange becomes lighter, and the propeller shaft and the companion flange are linked such that the first and second marks are as close together as possible.
With the linking structure pertaining to the present invention, when the propeller shaft and the companion flange are coupled, they are coupled such that the lighter and heavier unbalanced rotational masses are in opposition, so that the imbalance of the two components is canceled out and there is less imbalance overall in the power transmission device.
It is preferable if the companion flange is directly and rotatably supported by a bearing in the rotation transmission device.
The above-mentioned rotation transmission device can comprise an axle device having a final reduction device, and be structured such that the companion flange is attached to the input rotation shaft of the final reduction device.
In this case, the final reduction device can comprise a hypoid drive pinion and a hypoid driven gear that mesh with each other, the pinion shaft having this hypoid drive pinion can constitute the input rotation shaft, and the companion flange can be splined to the pinion shaft.
The linking method pertaining to the present invention is a method for linking a propeller shaft and a rotation transmission device in a power transmission device having a propeller shaft that transmits rotational drive force and a rotation transmission device that is linked to the propeller shaft and transmits rotational drive force. This method comprises the steps of measuring the rotational imbalance in the propeller shaft, providing a first mark indicating the direction of rotational imbalance in the propeller shaft, in the proximity of the linked portion of the propeller shaft, measuring the rotational imbalance of the companion flange linked to the propeller shaft in the rotation transmission device, providing a second mark indicating the direction of rotational imbalance in the companion flange, in the proximity of the linked portion of the companion flange, and linking the propeller shaft and the companion flange on the basis of the first and second marks.
With this linking method, it is preferable if the first mark is provided in the direction in which the unbalanced rotational mass of the propeller shaft becomes lighter, the second mark is provided in the direction in which the unbalanced rotational mass of the companion flange becomes heavier, and the propeller shaft and the companion flange are linked such that the first and second marks are as close together as possible. The structure may also be the opposite of this, in which the first mark is provided in the direction in which the unbalanced rotational mass of the propeller shaft becomes heavier, the second mark is provided in the direction in which the unbalanced rotational mass of the companion flange becomes lighter, and the propeller shaft and the companion flange are linked such that the first and second marks are as close together as possible.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.